I guess so, Jeff..

I've had problems like that,in the past, though, like a fuse that blows now and again or my old '66 650 Triumph that used to miss on one cylinder.at over about sixty miles an hour sometimes. It would never do it to order, only when I was desperately trying to keep up with mates who may have thought I was being a wimp. It felt like carburation but turned out in the end, after about a year of head scratching, it was one of the condensers. Maybe ohms were involved.

Ray..

 

I have a similar problem with my 3.4 Auto which I am not bothered about really but when I start the car it appears as if it is only firing on 5 cylinders. Very lumpy below 1500 rpm but once it is warm and if you run the revs over 1500 it clears and runs fine. I do have 9:1 pistons running E5 fuel so it might be that it does not like low revs when cold. Tried all the normal stuff like plugs and leads so I just live with it.

 

I would say the choke is set a bit rich/and or the carbs them selves are a little rich.
All engines with SU carbs run a little lumpy when the choke is on and the engine is cold.
Manual or otherwise.

 

https://simonbbc.com/custom-ht-lead-...ls-6-cylinder/

Peter
Looks to me as if you can bore acorn nuts out to 7mm and fit new ignition wires?
Rgds
David

 

Have been away & will get back to this task next week.
Thanks David, that looks promising, if the copper leads give me issues, I'll explore that.
Sorry Jeff will try & keep the guessing to a minimum.
R
Peter

 

I'm being an A-Hole again.
Not just here, but other forums with ignition and wiring problems.
Trouble shooting electrical problems has to be approached in a very logical and orderly method, if that isn't followed, then it turns into this guessing game of "lets try this" with out any understanding of how things work or where a given problem may lie.

My horn stopped working in my 51 Bentley, and I traced it down to the relay, where inside the rivet connecting the contacts had a cold connection _ no continuity across the rivet _ solution was to solder the rivet in place on both sides.

The same can go for a fuse box with rivets, and even the fuses themselves, they look OK, but the solder can oxidizes and cause bad connections; visual inspections are not good enough.
Ever wonder Lucas wiring is so bad, it's because of the cad plating on all the connections, it oxidizes and turns green/white. It does just the opposite it was supposed to do.
Even if the plating looks healthy, it isn't.
Bad connections cause fuses to go...

 

Hehe, no problems Jeff I'm just not that good with electricals, give me mechanicals any day!
Some useful information to be aware of though, appreciate it.
R
Peter

 

A saying I was told by an old boy many years ago, when I was a lad and he was still much younger than I am now, was - 'If you think it's ignition it will be fuel and if you think it's the carburettor it will be the ignition.'

It was worth remembering.

Ray

 

Guys installed new NGK BPR5ES Resistor Plugs gapped to .025" to go with the new Electronic Ignition & she started 1st push on the button.
Still running the copper core leads.
There is no more puff/puff miss from the exhaust, so I must have had two bad spark plugs. (remember I identified one by swapping a couple over)
Changed oil & filter & went for an hour drive & the car ran beautifully.
I one tiny oil leak after the run which appears to be coming from the oil feed pipe barrel union on the side of the block that feeds the back of the camshafts.
It's a hard one to get to now as I have the BW66 oil & Engine oil dipsticks close to the only space there!
Will address that with a flexible socket connection & install new copper gaskets with aircraft sealant.

I will look into getting new electronic carbon leads in the future, but for now she's running fine.
Thanks everyone for your help, really appreciate it.
Great forum
regards
Peter

 

No need for carbon leads, you know the saying "if it ain't broke, don't fix it"

There's enough resistance in the plugs (5k Ohm) with your solid copper wires so it won't bother the radio and any other electronics.

This is not a modern engine that requires a super hot spark to meet emission standards.
I find on older engines that if you would run too big of a gap with a super hot spark, the fuel mixture burns too long and too rapid.
This causes pre-ignition, and you don't want that, and you can't adjust the timing to get rid of it either.
There's no computer adjusting things on the fly with the spark or the fuel mixture.

I find things work better with a 25 thou, gap, regular wires and a normal 3 ohm coil. OR a 1.5 ohm coil with a 1.5 ohm resistor on the positive side of the coil (for negative ground cars)